Method of deactivating dust mite allergens

ABSTRACT

A method is provided for deactivating a Der-p and/or Der-f allergen which comprises volatilizing into a space to be treated a deactivating amount of a volatile oil selected from cajeput oil (tea tree oil) or an oil comprising one or more terpene hydrocarbons.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a Continuation of International ApplicationNo. PCT/GB01/01572, filed Apr. 9, 2001, which was published in theEnglish language on Oct. 18, 2001, under International Publication No.WO 01/76371 A1 and the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to a method of deactivating dustmite allergens.

[0003] Various allergens are known which are transported through the airto trigger a human reaction. For example, it has been known for a longtime that house dust can trigger allergenic reactions in humans, such asasthma and rhinitis. It was reported as early as 1928 that it was thedust mites in the dust that were the primary source of the allergenicresponse, but it was only in the 1960's that researchers appreciatedtheir significance.

[0004] It is believed that the feces of the house dust mite,Dermatophogoides farinae (known as Der-f) and Dermatophagoidespteronyssinus (known as Der-p), trigger the immune response of the body,thereby giving rise to well known allergenic symptoms. A review of thisis given in Experimental and Applied Acarology, 10: 167-186 (1991).

[0005] One way to overcome these allergenic responses has been to vacuumclean surfaces, such as carpets, that contain the dust mites and theirfeces thoroughly and often, but that is both time consuming (it has tobe regularly done to ensure an allergenic free environment) and is verydependant on the efficiency of the vacuum cleaner and filter bag used,e.g., micron filter bags or two layer vacuum bags.

[0006] An alternative method of creating an allergen-free environmenthas been to denature the allergen, for example, by using an allergendenaturant applied to airborne allergens by means of an aerosol spraydevice. Such a device produces an aerosol spray when activated and thisspray may be targeted at any space which is to be treated.

[0007] The allergens to be treated are airborne particles and the use ofa known aerosol spray device results in a low collision rate between theallergen denaturant and the airborne allergens. The practicalconsequence of such a low collision rate is that the allergen denaturantmust be used in a high amount in order to be effective. There may beother consequences such as, in the case where the aerosol spraycomposition includes a perfume or fragrance, a strong perfume smell or alimited fragrance choice.

[0008] PCT/GB98/02863 describes a method for deactivating allergensderived from the Der-f and/or Der-p dust mite species, which comprisescontacting the allergen with a deactivating amount of one or more of avariety of 28 deactivants as described. The deactivants which arespecified for use include cedarwood oil, hinoki oil and thymol(6-isopropyl-m-cresol).

BRIEF SUMMARY OF THE INVENTION

[0009] A method of deactivating at least one of a Der-p and a Der-fallergen is provided. The method comprises volatilizing into a space tobe treated a deactivating amount of a volatile oil by heating thevolatile oil to volatilize the oil, or by volatilizing the volatile oilfrom an ultra-sonic jet nebulizer, wherein the volatile oil is selectedfrom the group consisting of cajeput oil (tea tree oil) and an oilcomprising at least one terpene hydrocarbon.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0010] The foregoing summary, as well as the following detaileddescription of the invention, will be better understood when read inconjunction with the appended drawings. For the purpose of illustratingthe invention, there are shown in the drawings embodiments which arepresently preferred. It should be understood, however, that theinvention is not limited to the precise arrangements andinstrumentalities shown. In the drawings:

[0011]FIG. 1 is a graphical representation of the test results fromExample 1 below;

[0012]FIG. 2 is a graphical representation of the test results fromExample 2 below;

[0013]FIG. 3 is a graphical representation of the test results fromExample 3 below;

[0014]FIG. 4 is a graphical representation of the test results fromExample 4 below;

[0015]FIGS. 5 and 6 are graphical representations of the test resultsfrom Example 5 below;

[0016]FIG. 7 is a graphical representation of the test results fromExample 6 below;

[0017]FIG. 8 is a graphical representation of the test results fromExample 7 below;

[0018]FIG. 9 is a graphical representation of the test results fromExample 8 below;

[0019]FIG. 10 is a graphical representation of the test results fromExample 9 below; and

[0020]FIG. 11 is a graphical representation of the test results fromExample 10 below.

DETAILED DESCRIPTION OF THE INVENTION

[0021] We have now discovered a group of novel allergen denaturants forthe house dust mite Der-p allergen which are derived from natural oilsand which can be delivered as a vapor to deactivate the allergens.Accordingly, the present invention provides a method of deactivating aDer-p and/or Der-f allergen which comprises volatilizing into a space tobe treated a deactivating amount of a volatile oil selected from cajeputoil (tea tree oil) or an oil comprising one or more terpenehydrocarbons.

[0022] Suitable oils comprising one or more terpene hydrocarbons whichmay be used in the present invention are those which are genericallyreferred to as pinol, such as these sold under the names Unitene® D andUnitene® LE (Bush Boake Allen). The main component of both Unitene® Dand Unitene® LE comprises limonene as its major constituent. Unitene® Dcontains significant quantifies of cineole and terpinolene, whileUnitene® LE contains significant quantities of terpene alcohols.

[0023] Cajeput oil, which is generally known as tea tree oil, isobtained from the Melaleuca leucandra, Melaleuca quinquenervia, or otherMelaleuca species. The main components of tea tree oil are cineole andterpinene-4-ol.

[0024] There are various methods which can be used to volatilize thevolatile oils into the air, and these delivery methods are discussedbelow.

[0025] The volatile oil may be volatilized by the use of heat tovaporize the oil. For example, the volatile oil may be floated on waterin an oil burner or heated directly in an oil burner. Alternatively, thevolatile oil may be vaporized from a heated wick dipped into a reservoirof the volatile oil.

[0026] Another method of volatilizing the volatile oil is from anultra-sonic jet nebulizer, which contains water with the volatile oilfloated on the surface of the water.

[0027] A further method of volatilizing the volatile oil is by theventilation of a source of the volatile oil using an ion wind. An ionwind generates an ionized air flow which facilitates the evaporation anddispersal of the volatile oil into the air. A unipolar charge istransferred to the molecules of the oil which is evaporated. Optionally,the source of the volatile oil may be heated in order to assistevaporation. The ion wind not only facilitates the evaporation anddispersal of the volatile oil, but also has the added advantage that theion wind generating device has no moving parts and thus operates at verylow noise levels. The ion wind thus acts as an essentially silent fan.The charged molecules of the vaporized oil are attracted to particles inthe air with an opposite or neutral charge, and so may be more efficientat denaturing airborne allergens than uncharged molecules. The chargedmolecules are also attracted to surfaces in the environment which arebeing treated, and thus allergens on surfaces are also treated.

[0028] A method and apparatus for dispersing a volatile composition,such as a volatile oil, is described in our PCT Application No.PCT/GB99/04312.

[0029] It will be understood that in order to obtain the desired levelof the volatile oil evaporated into a room, the rate of evaporation ofthe oil, the surface area across which the volatile oil is evaporated,and the ion wind speed will need to be taken into account. Higher ionwind speeds will provide faster evaporation of the volatile components,and thus the surface area across which the volatile oil is evaporatedwill need to be adapted to the air flow speed.

[0030] The benefit of charging the molecules of the volatile oil usingan ion wind is two-fold. The individual molecules are attracted as theallergen particles and, since all of the molecules have the samepolarity charge, they are repelled one from another. Accordingly, themolecules tend to spread out to a great extent as compared to unchargedmolecules.

[0031] Allergen particles are normally electrically isolated from theirsurroundings and will typically be at a potential which is the same asthat of their surroundings. An isolated allergenic particle within acloud of electrically charged molecules is likely to cause distortion ofthe electrical field so that the attraction of the charged moleculesonto the allergen particle will be enhanced.

[0032] The volatile oil may be used as such, or may be presented in theform of an emulsion. Generally, the emulsion will be an oil-in-wateremulsion comprising up to about 5% by weight of the oil. The formationof emulsions is generally well known in the art and is described, forexample, in Modern Aspects of Emulsion Science, edited by Bernard P.Binks, The Royal Society of Chemistry (1998) and Surfactant Science andTechnology, Second Edition, Drew Myers, VCH Publishers, Inc (1992).

[0033] In a still further aspect of the present invention, the volatileoil is incorporated into a candle which is burnt in the space to betreated. In carrying out this aspect of the present invention, thecandle which is burnt will generally comprise at least about 2% byweight of the volatile oil, preferably at least about 5% by weight ofthe volatile oil, and more preferably at least about 10% by weight ofthe volatile oil.

[0034] By the term “candle” as used herein is meant a solid, semi-solidor gelled body of a combustible material which contains an axiallyembedded combustible fibrous wick. When the wick of a candle is lit, theheat so generated melts the combustible material, and the resultingliquid flows up the wick by capillary action and is combusted.

[0035] Typically, the combustible body of the candle may be a blend oforganic materials, such as beeswax, paraffin wax, montan wax, carnaubawax, microcrystalline wax, fatty alcohols, fatty acids, fatty estersand/or natural and synthetic resins. Clear candles may comprise as thecombustible material a gel comprising mineral oil containing blends ofdiblock and triblock copolymers based on synthetic thermoplasticrubbers, or a gel obtained by combining a liquid base material of ahydrogenated polyolefin, a gelling agent, and optionally a gel enhancingagent.

[0036] A wick normally extends longitudinally through the candle body.More than one wick may be used, if desired, but usually a single wick iscentrally disposed in the candle body. When a candle wick is ignited,the wick is adapted to burn gradually so that both the wick and thecandle body are consumed.

[0037] Typically, the weight of candle which is burnt in a particularspace to be treated will depend upon the actual volume of the space,e.g., room, to be treated. An appropriate allergen denaturing effect canbe obtained in accordance with the method of the invention by burning ina room having a volume of about 25 to 30 m³ a candle weighingapproximately 150 g before testing containing about 5% by weight of thevolatile oil for a period of about five hours. The amount of thevolatile oil which is released from the burning candle can be calculatedby weighing the candle at about one hour intervals.

[0038] The length of time for which the candle is burnt in the space tobe treated will generally be for up to about two hours, generally up toabout five hours, although in some circumstances the candle may be burntfor a longer period of time, such as about ten hours or more. However,it will be understood by those skilled in the art that an allergendenaturing effect will be obtained even if the candles containing theselected volatile oils are burnt for a lesser period of time.

[0039] The volatile oil may also be delivered by means of a nebulizer inwhich oil is floated on the surface of water in the nebulizer, or isprovided as an oil-in-water emulsion in the nebulizer. The nebulizercomprises a piezo-ceramic element which vibrates in the liquid (at 2-5MHz) and a plume of liquid is generated by ultrasonic streaming. A densecloud of very small droplets (less than about 5 μm) is then expelledfrom the surface of the liquid. A fan may be used to assist theexpulsion of the nebulized droplets from the vessel.

[0040] The present invention will be further described with reference tothe following specific, non-limiting Examples.

[0041] Control Pre-Treatment Allergen Level

[0042] When using house dust for allergen denaturing tests, an inherentdifficulty is the variability of the amount of allergen in each smallsample, even when taken from the same dust reservoir. The amount of dustin the pre-treatment sample must be accurately estimated in order todetermine the extent of any allergen denaturing. In these tests, thedust sample was applied to the test exposure surface and then one halfof this surface dust was removed to measure the control pretreatmentallergen level of that specific sample. Each control was directlyrelevant to each sample, which gave the best possible estimate of thelevel of allergen in the sample before exposure to possible denaturant.

[0043] Unless specified, the following Examples all measure thereduction of the house dust mite (Dermatophagoides pteronyssinus)allergen (Der-p1).

EXAMPLE 1

[0044] House dust was passed through a number of sieves and the fractionsmaller than 53 μm was collected. 0.1 g of dust was placed in a smallsieve to distribute it evenly over the test surface, an aluminum tray0.6 m×1 m. The dust was applied to the tray by moving the sievecontinuously over the surface. As a pre-treatment control, one half ofthe dust was then removed by suction onto an inline filter and theweight was recorded. The tray was then placed in a plastic lined boothmeasuring 0.8 m×0.8 m×1.5 m. An oil burner containing 800 μl of the testsample floated on 6 ml of distilled water was placed in the booth, andthe booth was sealed. The oil burner candle was lit and allowed to burnuntil all the liquid had been vaporized (approx. 1 hour). The candle wasthen smothered and the dust was left exposed in the booth. After 24hours, the tray was removed, the dust was collected from it, and itsweight was recorded. The booth was washed with strong detergent betweentests of the same chemical and the booth lining was changed between testchemicals.

[0045] The test samples evaluated were:

[0046] Hinoki Oil (comparative)

[0047] Citronella Oil (comparative)

[0048] Tea Tree Oil

[0049] Pinol (Unitene® D)

[0050] Pinol (Unitene® LE)

[0051] The test samples were assayed for Der-p1 using an ELISA (EnzymeLinked Immunosorbent Assay) to determine the allergen content, which wasthen related to the weight of dust that had been present in each sample.All of the samples were normalized to compare the amount of allergenexpected to be present in a 0.1 g sample of dust. The percentagedifferences between the control sample and the exposed samples were thenobtained and are presented in FIG. 1.

[0052] The differences in the amounts of allergen reduction afterexposure to any of the volatile oils released from the oil burner whencompared to the inherent loss in sampling were significant when comparedin a two-tailed t-test. Therefore, in conditions of the test, exposureto the above oils released from an oil burner resulted in a significantreduction in the allergen contained in the dust samples.

EXAMPLE 2

[0053] House dust was passed through a number of sieves and the fractionsmaller than 53 μm was collected. 0.1 g of dust was placed in a smallsieve to distribute it evenly over the test surface, an aluminum tray0.6 m×1 m. The dust was applied to the tray by moving the sievecontinuously over the surface. As the pre-treatment test control, onehalf of the dust was then removed by suction onto an in-line filter andthe weight was recorded. The tray was then placed in a plastic linedbooth 0.8 m×0.8 m×1.5 m.

[0054] For control tests, dust was distributed on the tray, thepre-treatment control was collected, and the dust was left in the boothfor 24 hours. The tray was then removed and the dust was collected fromthe tray and weighed. In subsequent tests, 800 μl of volatile oil wasadded to 150 ml of distilled water in a nebulizer. The tests were thencompleted as in the control tests. The booth was washed with strongdetergent between tests.

[0055] The samples evaluated were:

[0056] Tea Tree Oil

[0057] Pinol (Unitene® D)

[0058] Pinol (Unitene® LE)

[0059] The collected dust samples were assayed for Der-p1 using an ELISAto determine the allergen contents, which were then related to theweight of dust that had been present in each sample. All of the sampleswere normalized to compare the amount of allergen expected to be presentin a 0.1 g sample of dust. The percentage differences between thecontrol sample and the exposed samples were then obtained and arepresented in FIG. 2.

[0060] The differences in the amounts of allergen reduction afterexposure either to tea tree oil or Unitene® D released from thenebulizer, when compared to the loss in sampling control, weresignificant (P<0.05) when compared on a two tailed t-test. Therefore, inthe conditions of the test, exposure to either tea tree oil or Unitene®D released from a nebulizer resulted in a significant reduction in theallergen contained in the dust samples.

EXAMPLE 3

[0061] Dust was collected from vacuum cleaner bags and passed through aseries of sieves down to 53 microns. Clean petri dishes were labeledwith the chemical to be tested and lined with filter paper. 0.3 g ofdust was added to each dish and spread evenly over the filter paper. 0.1g of dust was then removed from the filter paper for a control sample.The remaining dust was then redistributed evenly over the filter paper.2.4 g±0.2 g of test chemical was sprayed onto the dust sample. The dustsample was left open to the air until the filter paper was dry. The dustwas collected into eppendorfs and the weight of dust recovered wasmeasured. 1 ml of 1% Bovine Serum Albumin-Phosphate BufferedSaline-Tween (BSA-PBS-T) was added to the control samples. 1 ml of 5%BSA-PBS-T was added to the test samples. The samples were left overnightin the refrigerator and then centrifuged for 5 minutes at 13,000 rpm.The supernatant was pipetted into an eppendorf for assay by Der-p1ELISA.

[0062] The test liquids were:

[0063] Distilled water

[0064] 2% Tea Tree Oil in distilled water (plus 0.1% Tween)

[0065] 2% Citronella Oil in distilled water (plus 0.10% Tween)

[0066] 1% Thymol in distilled water (plus 0.8% Tween)

[0067] 2% Hinoki Oil in distilled water (plus 0.1% Tween)

[0068] 2% Tannic Acid

[0069] Five replicates were completed for each test liquid. The allergencontent of the control for each replicate was compared with the testsample allergen. The percentage reductions in allergen between thecontrol and the test were determined for each replicate. The averageallergen reductions of all five replicates are presented in FIG. 3.

[0070] The water tests showed an average allergen reduction of 34.2%.The addition of Tea Tree Oil to the dust reduced the allergen by another29.6%. This difference was significant when compared on a t-test(t=4.08). Thymol reduced the allergen by 23.6% more than the water alonetests, which difference was significant when compared on a t-test(t=3.3). Finally, the addition of tannic acid to the dust reduced theallergen by an average of 99.15% in the tests.

[0071] When taking the reduction of allergen in the water samples intoaccount, some of the test liquids still significantly reduced theallergen content in the dust samples. Tannic acid was used as a positivecontrol, as it is known to denature allergen, and its effect wasrecorded in the tests. Tea tree oil significantly reduced the allergencontent in the dust samples.

EXAMPLE 4

[0072] Method

[0073] The tests were completed in 28 m³ test rooms with no windows anda door that was closed throughout the duration of the test. The roomsdid not contain any furniture and had easily cleaned floors ofnon-reactive resin. Six test areas 0.7 m×0.7 m were marked out on thefloor of each room with tape. Each test area was divided into twohalves. Test dust had been obtained from household vacuum cleaner bags.House dust was passed through a number of sieves and the fractionsmaller than 53 microns was collected. 0.1 g of dust was placed in asmall sieve to distribute it evenly over the test surface. The dust wasapplied by moving the sieve continuously over the surface. Dust wasremoved from half of each of the six test areas by suction of 20 l/minthrough an in-line glass fiber filter (2.5 cm diameter) and the weightrecorded as the pre-treatment controls. The selected test candlesweighing approximately 150 g before testing were lit and placed in therooms for five hours. The candles were then smothered, and the dust wasleft exposed in the rooms for sixteen hours. The dust was then collectedas for the controls and weighed.

[0074] The collected samples were assayed by Der-p1 ELISA to determinethe allergen contents, which were then related to the weight of dustthat had been present in each sample. All the samples were normalized tocompare the amount of allergen expected to be present in a 0.1 g sampleof dust. The percentage differences between the control samples and theexposed samples were then obtained and are presented in FIG. 4.

[0075] During the five hour burn period, approximately 27 g of each ofthe candles was burnt. For candles B and C detailed below, this equatedto a release rate of 270 μl of essential oil per hour.

[0076] Tests completed were:

[0077] Test Description

[0078] A. Unfragranced candle, room relative humidity (rh)

[0079] B. 5% w/w Tea Tree oil candle, room rh

[0080] C. 5% w/w Unitene LE candle, room rh

[0081] M. No Treatment, room rh

[0082] The room rh recorded during the tests was between 50 and 57%.

[0083] Results

[0084] It can be seen from FIG. 4 that there is a significant reduction(P<0.05) Der-p1 allergen content of dust exposed to both the tea treeoil (36.5%) and Unitene® LE (30.6%) candle as compared to the notreatment control (t=3.19 and 2.38 respectively).

[0085] Discussion

[0086] The results indicate that a significant reduction in allergen canbe achieved in a room environment by burning candles containing eithertea tree oil or Unitene® LE for five hours.

EXAMPLE 5

[0087] Method

[0088] British (containing Der-p1) or American (containing Der-f1) housedust was passed through a number of sieves and the fraction smaller than53 microns was collected. 0.1 g of dust of the selected origin wasplaced in a small sieve and distributed evenly over the test surface, analuminum tray 0.6 m×1 m, which could be easily cleaned with strongdetergent. The dust was applied to the tray by moving the sievecontinuously over the surface. Half of the dust was then removed bysuction of 20 L/min through an in-line glass fiber filter (2.5 cmdiameter) and the weight recorded as the pre-treatment control. The traywas then placed in a plastic booth 1 m×0.7 m×0.7 m.

[0089] The candle to be tested weighing approximately 150 g was placedin the booth. The candle was lit and the booth door closed. Afterapproximately two hours, the temperature and humidity in the booth weremeasured. The candle was allowed to burn for a total of five hours andwas then smothered and the dust left exposed in the booth for 17 hours.The tray was then removed and the booth ventilated. The dust wasvacuumed from the tray onto a filter and weighed.

[0090] Test candles evaluated were:

[0091] Control candle

[0092] 5% Tea Tree Oil candle

[0093] 5% Pinol (Unitene® LE) candle

[0094] Six single exposure replicates were completed for each candle.The collected samples were assayed by Der-p1 or Der-f1 ELISA todetermine the allergen contents, which were then related to the weightof dust that had been present in each sample. All the samples werenormalized to compare the amount of allergen expected to be present in a0.1 g sample of dust. The percentage differences between the controlsample and the exposed samples were then obtained.

[0095] The results for Der-p1 are presented in FIG. 5 and the resultsfor Der-f1 are presented in FIG. 6.

[0096] The reduction of Der-p1 allergen concentration in the dust wassignificant after exposure to either the tea tree oil or Unitene® LEcandles, and the reduction in Der-f1 allergen concentration in the dustwas significant after exposure to the tea tree oil candle.

EXAMPLE 6

[0097] The general procedure of Example 5 was repeated but with threerepeated exposures to a candle containing 5% tea tree oil burnt for fivehours (i.e., total 15 hours burn), as compared to a single exposure to acandle containing 5% tea tree oil burnt for 5 hours or to a controlcandle. Six replicate experiments were completed.

[0098] The results are given in FIG. 7. It will be noted that repeatedexposure further reduced the Der-p1 allergen concentration of dust on asurface.

EXAMPLE 7

[0099] Experiments were completed using the same method as described inExample 5 except that dust samples were exposed in each booth at thesame time. 0.025 g of dust was distributed evenly over a 0.32 m²aluminum tray. Half of this was then removed as a control sample asdescribed in Example 5 and the tray was placed in the booth. Five othertrays were prepared in this way and placed in the booth. The six trayscontaining the test dust samples were exposed in the booth to a fivehour burn of the selected candle. The trays were left exposed in thebooth for a further 17 hours, and the test dust samples were thencollected and assayed by the appropriate ELISA. FIG. 8 show a comparisonof the % Der-p1 allergen reduction after exposure to clear gel candlescontaining 0% (control) or 5% tea tree oil.

[0100] The reduction of allergen concentration in the dust wassignificant after exposure to the gel candle containing tea tree oil.

EXAMPLE 8

[0101] Experiments were completed using the same method as described inExample 4. However, instead of burning a candle, a nebulizer was used todeliver the volatile oils.

[0102] The ultra-sonic jet nebulizer used in Example 2 was used in theseroom tests. When the nebulizer was activated, a jet of cold, ultra-finemist was expelled from the top of the reservoir. Tests were completedwith 5 ml of either tea tree oil or Unitene® D floated on top of 150 mldeionized water in the nebulizer.

[0103] The nebulizer was activated for three hours. It is not knownexactly how much of the volatile oil was released, as some of thewater/oil mixture remained in the nebulizer at the end of the test.Controls were completed with deionized water alone in the nebulizer. Theresults are given in FIG. 9.

[0104] There was a significant reduction of the allergen content of thedust after exposure to the tea tree oil or Unitene® D.

EXAMPLE 9

[0105] Experiments were completed as detailed in Example 1, but withAmerican house dust. Test dust samples were exposed to oil burners insmall booths containing 800 μl of tea tree oil floated on 6 ml ofdistilled water. These were compared dust lost in sampling. Dust sampleswere collected after 24 hours and assayed by Der-f1 ELISA. The resultsare given in FIG. 10.

[0106] There was a significant reduction of the allergen content of thedust after exposure to the tea tree oil.

EXAMPLE 10

[0107] Experiments were completed using the same method as described inExample 4. However, instead of burning a candle, oil burners were usedto deliver the tea tree oil.

[0108] Two types of oil burners were used in the tests. Small oilburners were used in the small booth tests (detailed in Example 4) andin one of the test room tests. The oil burners were ceramic with a smalldish with a 15 ml capacity to hold the water and volatile oil. A singletea candle was placed under the suspended dish to evaporate the waterand tea tree oil. Large oil burners were used in the remaining testscompleted in 28 m³ test rooms. These were also ceramic and had a largedish with a 35 ml capacity and were wider in the base so that three teacandles could be placed under the dish to evaporate this larger amountof liquid more efficiently. The tea tree oil was always floated on waterin the oil burners as this regulated the temperature and enabled acontrolled release rate of the tea tree oil.

[0109] Two large oil burners were used in most of the room tests, asthis was a much larger volume over which to deliver the water and teatree oil. Two large oil burners contained in total 65 ml of deionizedwater and, where specified, 5 ml of the tea tree oil. This was not adirect translation of the small booth tests as it was found that thiswould have been unrealistic (336 ml water and 44.8 ml test chemical).They were placed in the rooms and the candles burnt until all of theliquid had evaporated. Tests were completed with tea tree oil. Controlswere conducted with deionized water alone in the oil burners. Toquantify any effect due to the candles, tests were conducted with sixtea candles alone. One test was also completed with a small oil burnercontaining 6 ml of water and 800 μl of tea tree oil, so that acomparison could be made with the small booth tests. The results aregiven in FIG. 11.

[0110] There was a significant reduction of the allergen content of thedust after exposure to the tea tree oil.

[0111] It will be appreciated by those skilled in the art that changescould be made to the embodiments described above without departing fromthe broad inventive concept thereof. It is understood, therefore, thatthis invention is not limited to the particular embodiments disclosed,but it is intended to cover modifications within the spirit and scope ofthe present invention as defined by the appended claims.

We claim:
 1. A method of deactivating at least one of a Der-p and aDer-f allergen which comprises volatilizing into a space to be treated adeactivating amount of a volatile oil by heating the volatile oil tovolatilize the oil, or by volatilizing the volatile oil from anultra-sonic jet nebulizer, wherein the volatile oil is selected from thegroup consisting of cajeput oil (tea tree oil) and an oil comprising atleast one terpene hydrocarbon.
 2. The method according to claim 1,wherein the volatile oil is heated in order to volatilize it into thespace.
 3. The method according to claim 2, wherein a source of thevolatile oil comprises a wick dipped into a reservoir of the volatileoil.
 4. The method according to claim 1, wherein the volatile oil isvolatilized into the space from an ultra-sonic jet nebulizer.
 5. Themethod according to claim 1, wherein the volatile oil is provided as awater-in-oil emulsion containing not more than about 5% by weight of thevolatile oil.
 6. The method according to claim 1, wherein the volatileoil is incorporated into a candle which is burnt in the space to betreated.
 7. The method according to claim 6, wherein the candlecomprises at least about 2% by weight of the volatile oil.
 8. The methodaccording to claim 7, wherein the candle comprises at least about 10% byweight of the volatile oil.
 9. The method according to claim 6, whereinthe candle is burnt for at least about 2 hours.
 10. The method accordingto claim 1, wherein the oil comprising at least one terpene hydrocarboncomprises a pinol.